1. Field of the Invention
The invention relates to a resist pattern-forming method.
2. Discussion of the Background
A reduction in the line width of a resist pattern used for lithography has been desired along with miniaturization of the structure of electronic devices (e.g., semiconductor devices and liquid crystal devices). A fine resist pattern having a line width of about 90 nm can be formed using short-wavelength radiation (e.g., ArF excimer laser light) and a radiation-sensitive resin composition that responds to short-wavelength radiation. However, it will be required to form a finer resist pattern in the future.
It is considered that a high resolution similar to that achieved when using a light source having a shorter wavelength can be implemented by liquid immersion lithography even if a light source having the same exposure wavelength is used. Therefore, liquid immersion lithography has attracted attention as technology that achieves high resolution while suppressing an increase in cost in the production of semiconductor devices that requires a large capital investment. However, liquid immersion lithography has a drawback in that a deterioration in performance may occur due to a deterioration in the resist film caused by elution of a substance from the resist film into the immersion medium or the like, a local change in refractive index of the immersion medium may occur due to the eluted substance, or the surface of the lens may be contaminated by the eluted substance, so that the lithographic properties may deteriorate (see WO04/068242).
The above drawback may be eliminated by changing the resist composition so that the resist film exhibits higher hydrophobicity.